#14320 How multiple lockfiles & first-party source plugins work for Pylint, MyPy, Flake8 Issue created by Eric-Arellano We allow you to create first-party source plugins and set via

[pylint].source_plugins

etc, which expects addresses to

python_source

targets. Those can depend on third-party requirement like any normal code, via

python_requirement

. We currently consume the requirements via the tool lockfile: pants/src/python/pants/backend/python/lint/pylint/rules.py Lines 103 to 113 in </pantsbuild/pants/commit/f258544f8cf9a3fe135a40e587d27ff8fa0e42c8|f258544> Our tool lockfile generation knows to include those requirements: pants/src/python/pants/backend/python/lint/pylint/subsystem.py Lines 292 to 296 in </pantsbuild/pants/commit/f258544f8cf9a3fe135a40e587d27ff8fa0e42c8|f258544> That means that that tool lockfile codepath is ignoring the

resolve

field of those

python_requirements

. -- However,

resolve

is still relevant! You can run Pants goals on that first party plugin code directly, like anything else. When you do that, those targets will be the inputs to our

pex_from_targets.py

code, which determines the

resolve

by inspecting the input targets: pants/src/python/pants/backend/python/lint/pylint/rules.py Lines 91 to 102 in </pantsbuild/pants/commit/f258544f8cf9a3fe135a40e587d27ff8fa0e42c8|f258544> -- Practically, what this all means is that multiple resolves is very useful for source plugins. You can define a distinct resolve for your plugin code, which lets you avoid introducing dependencies just needed for your plugin into your main projects. When you run Pants on that plugin code directly, it will do the right thing. When you run Pants on code that uses a different resolve than your plugin, Pants can still handle that. It won't complain about conflicting resolves, and the tool lockfile will still have the requirements you need to make things work. If you're fine with using a single resolve for everything, you can ignore all this nuance and Pants will do the right thing. pantsbuild/pants